Hi, I was able to resolve the issue. Please follow below steps
In VirtualBox, Go to settings > General - Select the Version to Ubuntu (64-bit) and Click on OK. Start the VM you should be able to run it now.
In case if the Ubuntu (64-bit) is not listed in the dropdown, it means virtualization is not ebabled. you need to enable Virtualization by Rebooting the host, go in to BIOS and enable Virtualization. Exit the BIOS, making sure you save changes.